This invention relates to an exhaust system for a motorcycle. More particularly, it is concerned with a method for mounting the exhaust system on the frame body of the mototcycle so that it may be fixedly secured to the motorcycle body.
As shown in FIG. 1 of the accompanying drawing, it has been a usual practice in the manufacture of the motorcycle that an engine 1 is mounted on a frame 2 of the motorcycle body through a plurality of mounting members 3 made of a resilient buffer material with a view to preventing vibrations from the engine 1 in motion from propagating to a motorcycle rider through the frame 2, and that the front end of an exhaust pipe 4 is fixedly secured to an exhaust port 5 of the engine, and a muffler (or mufflers) 6 connected with the exhaust pipe 4 is fixed to the rear part of the frame 2 of the motorcycle body by means of threaded bolts, etc.. In other words, the exhaust system 4, 6 of the engine 1 is generally fixed at two points i.e., at the exhaust port of the engine and the rear part of the motorcycle frame.
In the above-described construction of the two-point support of the exhaust system, the exhaust system 4, 6 is subjected to vibration due to vibration of the engine 1 and vibration of the motorcycle frame 2 per se. In this case, since there is a considerable span of length between the fixed point of the exhaust pipe to the engine 1 and the rear end of the muffler, and the weight of the exhaust system is heavy, the vibrations from the exhaust system is to a considerable extent.
Therefore, in some cases, vibrations from the exhaust system 4, 6 amplifies the vibration from the engine 1, which propagates through the steering handle, foot steps, fuel tank, rearview mirror, and so forth to cause disagreeable feeling to the rider.
Also, at the start of the engine 1, it tends to deflect considerably, on account of which the exhaust pipe 4 is twisted to apprehensively cause a stress at the connected part between the exhaust pipe 4 and the exhaust port 5.